Hydraulic Oil Well Pumping System, and Method for Delivering Gas From a Well

Abstract

A hydraulic oil well pumping system is provided. The system uses a pump to exert hydraulic pressure against a reciprocating lift piston over a wellbore. The lift piston is operatively connected to a rod string and downhole pump for pumping oil from a wellbore. Thus, oil is pumped from the wellbore as the rod string and downhole pump move between upper and lower rod positions. In addition, the system includes at least one compressor cylinder having a compressor piston that reciprocates with the lift piston in order to compress produced gas at the surface. A method for compressing gas while pumping oil from a wellbore using such a system is also provided herein.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Ser. No. 61/766,664, filed Feb. 19, 2013. That application is entitled “Hydraulic Oil Well Pumping System, and Method for Delivering Gas From a Well,” and is incorporated herein in its entirety by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to the field of hydrocarbon recovery operations. More specifically, the present invention relates to hydraulically actuated pumping units for the production of hydrocarbon fluids, and to the compression of produced gas for pressured delivery into a gas line.

2. Technology in the Field of the Invention

In the drilling of oil and gas wells, a wellbore is formed using a drill bit that is urged downwardly at a lower end of a drill string. After drilling to a predetermined depth, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular area is thus formed between the string of casing and the surrounding formations.

A cementing operation is typically conducted in order to fill or “squeeze” the annular area with columns of cement. The combination of cement and casing strengthens the wellbore and facilitates the zonal isolation of the formations behind the casing.

It is common to place several strings of casing having progressively smaller outer diameters into the wellbore. A first string may be referred to as surface casing. The surface casing serves to isolate and protect the shallower, fresh water-bearing aquifers from contamination by any other wellbore fluids. Accordingly, this casing string is almost always cemented entirely back to the surface.

The process of drilling and then cementing progressively smaller strings of casing is repeated several times until the well has reached total depth. In some instances, the final string of casing is a liner, that is, a string of casing that is not tied back to the surface. The final string of casing, referred to as a production casing, is also typically cemented into place.

As part of the completion process, the production casing is perforated at a desired level. This means that lateral holes are shot through the casing and the cement column surrounding the casing. The perforations allow hydrocarbon fluids to flow into the wellbore. Thereafter, the formation is optionally acidized and/or fractured.

To prepare the wellbore for the production of hydrocarbon fluids, a string of tubing is run into the casing. A packer is optionally set at a lower end of the tubing to seal an annular area formed between the tubing and the surrounding strings of casing. The tubing then becomes a string of production pipe through which hydrocarbon fluids may be lifted. In some instances, produced gas is permitted to travel up the wellbore through the annular area.

In order to carry the hydrocarbon fluids to the surface, a pump may be placed at a lower end of the production tubing. This is known as “artificial lift.” In some cases, the pump may be an electrical submersible pump, or ESP. ESP's utilize a hermetically sealed motor that drives a multi-stage pump. More conventionally, oil wells undergoing artificial lift use a downhole reciprocating plunger-type of pump. The pump has one or more valves that capture fluid on a down stroke, and then lift the fluid on the upstroke. This is known as “positive displacement.” In some designs such as that disclosed in U.S. Pat. No. 7,445,435, the pump is able to both capture fluid and lift fluid on each of the down stroke and the upstroke.

Conventional positive displacement pumps define a barrel that is reciprocated at the end of a “rod string.” The rod string comprises a series of long, thin joints of pipe that are threadedly connected through couplings. The rod string is attached to a pumping unit at the surface. The pumping unit causes the rod string to move up and down within the production tubing to incrementally lift production fluids from subsurface intervals to the surface.

Most pumping units on land are so-called rocking beam drive units. Rocking beam units typically employ electric motors or internal combustion engines having a rotating drive shaft. The shaft turns a crank arm, or possibly a pair of crank arms. The crank arms, in turn, have heavy, counter-weighted flywheels. The flywheels rotate along with the crank arms. Rocking beam units also have a walking beam. The walking beam pivots over a fulcrum. One end of the walking beam is mechanically connected to the crank arms. As the crank arms and flywheels rotate, they cause the walking beam to reciprocate up and down over the fulcrum.

The opposite end of the walking beam is a so-called horse head. The horse head is positioned over the well head at the surface. As the walking beam is reciprocated, the horse head cycles up and down over the wellbore. This, in turn, translates the rod and attached pump up and down within the wellbore. A drawing and further description of a walking beam unit are provided in U.S. Pat. No. 7,500,390, which is incorporated herein in its entirety by reference.

Another type of pumping unit is a hydraulic actuator system. These systems employ an elongated cylinder that is positioned over a wellbore. The cylinder is axially aligned with the vertical wellbore and houses a reciprocating piston. The cylinder cyclically receives fluid pressure through an external oil line. As fluid is injected through the oil line and into the cylinder under pressure, the piston is caused to move linearly within the cylinder. This, in turn, raises the connected rod string, causing the pump to undergo an upstroke. When fluid pressure is released from the cylinder, the rod string is lowered due to gravitational forces, causing the connected downhole pump to undergo a downstroke.

Surface hydraulic actuator systems have been used successfully for many years. Such systems offer a beneficially long stroke length for the downhole plunger pump. Such systems are also ideal for urban environments where a small footprint is demanded. Further, such systems offer the ability to operate more than one well from a single surface installation.

It is uniquely observed by the inventor herein that energy generated by the gravitational forces exerted on the piston of a hydraulic pumping system could be used as a source of “free” work. At the same time, a need exists to compress gas being incidentally produced from the well on the back side of the production tubing. Therefore, it is proposed herein to employ gravitational forces available from the falling piston to compress gas as it is delivered into a gas line.

BRIEF SUMMARY OF THE INVENTION

An oil well pumping system is first provided herein. The pumping system cyclically directs a hydraulic fluid such as a clean oil into a lift cylinder. As the oil is pumped into the cylinder, the piston causes a rod string and connected downhole pump to move up within a wellbore. This is an upstroke. Then, as the hydraulic fluid is released from the lift cylinder, the rod string and connected downhole pump drop within the wellbore due to gravitational forces. This is a downstroke.

Reciprocation of the lift piston and connected rod string and downhole pump causes reservoir fluids to be produced from a wellbore and up to the surface through positive displacement. Beneficially, the system also uses the energy generated by gravitational forces as the piston and rod string move in the downstroke to compress produced gas at the surface. This, in turn, moves gas downstream for treating, for sale, or for use as a combustible fuel.

In one aspect, the oil well pumping system first includes an elongated hydraulic lift cylinder. The lift cylinder is positioned over the wellbore. The cylinder is preferably disposed vertically over an associated wellhead.

The oil well pumping system also includes a lift piston and a lift cylinder rod. The lift piston and the lift cylinder rod reside within the lift cylinder and move together between upper and lower rod positions. The lift cylinder rod defines an elongated rod while the piston provides an annular seal between the lift cylinder rod and the surrounding lift cylinder. Hydraulic pressure cyclically acts against the lift piston to create an upstroke and a down stroke for the lift cylinder rod.

The oil well pumping system further has a rod string. The rod string is operatively connected to the lift piston. This means that when the piston reciprocates, the rod string reciprocates with it. The rod string extends downwardly from a polish rod at the wellhead and into a string of production tubing in the wellbore. The rod string has a downhole pump connected to it for lifting fluids to the surface in response to reciprocation of the rod string.

In one aspect, the lift piston is operatively connected to the rod string by means of a harness system. The harness system is connected to a lower end of the lift cylinder rod below the lift cylinder. The harness system is also connected to an upper end of the polish rod. The harness system has a block for receiving an upper end of the polish rod, and a clamp for securing the polish rod over the block.

The oil well pumping system also has at least one compressor cylinder. The compressor cylinder defines a barrel that houses a compressor piston. Thus, the oil well pumping system also includes a compressor piston in each compressor cylinder. The compressor pistons are configured to reciprocate within the respective compressor cylinders in response to movement of the harness system.

The oil well pumping system may also include a hydraulic pump. The pump is powered by a prime mover. The prime mover may be an electric motor, an internal combustion engine, or other driver.

The oil well pumping system may further include a directional control valve. The directional control valve shifts between upstroke and downstroke flow positions. When the valve is in its upstroke position, it directs hydraulic fluid such as oil from the pump and into the annular area formed below the piston between the lift cylinder rod and the surrounding lift cylinder. When the directional control valve is in its downstroke (or neutral) position, it receives reverse flow from the annular area and allows the gravity-induced fall of the lift piston and connected rod string.

The oil well pumping system also has an oil line. The oil line connects the pump and the hydraulic lift cylinder. The control valve is positioned in the oil line so that it can control flow between the pump and the cylinder in response to electrical signals. The signals are sent by an electrical control system that shifts the directional control valve between its upstroke and downstroke flow positions.

A fluid reservoir is also provided. The fluid reservoir contains hydraulic fluid to be supplied to the pump.

The oil well pumping system may also comprises a reservoir line. The reservoir line transmits hydraulic fluid from the cylinder back to the reservoir.

The compressor cylinders are in fluid communication with a gas line at a well site. The gas line extends from the wellhead and carries non-condensable fluids that are produced from the wellbore. The non-condensable fluids, such as methane gas, travel from the subsurface reservoir and up the wellbore behind the string of production tubing. The non-condensable fluids then exit the wellbore through the gas line at the wellhead. Check valves are provided so that gas flows through the check valves and into the compressor cylinders on the upstrokes, but then flows down the gas line as pressure in the pipe is increased on the down strokes.

A method of compressing produced gas at a well site is also provided herein. In the method, the well site has a wellbore that extends into an earth surface. The well site utilizes a pumping system that cyclically directs a hydraulic fluid such as a clean oil into a lift cylinder. As the oil is pumped into the lift cylinder, pressure acts against a piston, causing a rod string and connected downhole pump to move up within the wellbore as an upstroke. Then, as the hydraulic fluid is released from the lift cylinder, the rod string and connected downhole pump drop within the wellbore as a down stroke.

Reciprocation of the lift piston and operatively connected rod string and downhole pump causes reservoir fluids to be produced from a wellbore and up to the surface through positive displacement. Beneficially, the system also uses the energy generated by gravitational forces as the piston and rod string move in the downstroke to compress produced gas at the surface.

In one aspect, the method first comprises providing an elongated hydraulic lift cylinder. The lift cylinder is positioned over the wellbore. The lift cylinder includes a lift piston that is movable between upper and lower rod positions. The lift piston creates an annular seal below the piston between a lift cylinder rod and the surrounding lift cylinder. Hydraulic pressure acts against the lift piston to cause the lift piston and connected lift cylinder rod to move.

The method also includes operatively connecting the lift piston to a rod string. This may be done through a harness system and a polish rod between the lift piston and the rod string. When the lift piston reciprocates, the polish rod and connected rod string reciprocate with it. Preferably, the rod string moves within a string of production tubing that extends down to the depth of a subsurface reservoir. The rod string has a downhole pump connected to it for lifting fluids to the surface in response to reciprocation of the rod string.

The method also includes providing a hydraulic pump. Preferably, the pump is a variable displacement piston pump, although a fixed displacement pump may be used. The pump is powered by a prime mover. The prime mover may be an electric motor, an internal combustion engine, or other driver.

The method also has the step of connecting the pump and the hydraulic cylinder with an oil line. The oil line transmits hydraulic fluid from the pump to the cylinder.

The method may also have the step of providing a fluid reservoir. The reservoir contains hydraulic fluid to be supplied to the pump. A reservoir line transmits hydraulic fluid from the cylinder back to the reservoir.

The method further includes providing at least one compressor cylinder. Each compressor cylinder has a compressor piston that is movable between upper and lower rod positions in response to movement of the lift piston. Thus, the compressor pistons are operatively connected to the lift piston.

In addition, the method includes placing the at least one compressor cylinder in fluid communication with a gas line. The gas line resides at the surface and is used to transport non-condensable hydrocarbon fluids such as methane and ethane. Additional components may include hydrogen sulfide, carbon dioxide, propane, and argon.

Further, the method has the step of producing non-condensable hydrocarbon fluids from the wellbore and into the gas line. Production is preferably done by allowing gases to migrate from a subsurface reservoir and up the wellbore behind the string of production tubing. The gases are directed into the gas line at the wellhead.

The method additionally provides for reciprocating the compressor piston in order to increase pressure in the gas line. When the compressor piston moves on its upstroke, it draws gas in through a check valve at the wellhead. Then, when the compressor moves down on its downstroke, it moves the produced gas along the gas line downstream.

Also, the method includes reciprocating the lift piston and mechanically connected rod string within the wellbore. This step is the natural result of operation of the hydraulic pumping system having gas compression over time in order to pump oil from the wellbore.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the present inventions can be better understood, certain illustrations, charts and/or flow charts are appended hereto. It is to be noted, however, that the drawings illustrate only selected embodiments of the inventions and are therefore not to be considered limiting of scope, for the inventions may admit to other equally effective embodiments and applications.

FIG. 1 is a side view of a hydraulic oil well pumping system of the present invention, in one embodiment. The hydraulic oil well pumping system is used for producing hydrocarbon fluids from a subsurface formation to the surface at a well site as well as for compressing produced gas. Portions of the system are shown schematically.

FIG. 2 is an enlarged side view of a portion of the hydraulic oil well pumping system of FIG. 1. Here, the lift cylinder, the polish rod, and two compressor cylinders are more clearly seen.

FIG. 3 is a side cross-sectional view of a one of the compressor cylinders of FIG. 2, in one embodiment. A compressor piston is shown in mid-stroke.

FIG. 4A is schematic view of a hydraulic pumping system of the present invention, in one arrangement. Here, a lift cylinder piston and an operatively connected compressor cylinder piston are on their down strokes. Produced gas is being moved to a downstream facility along a gas line.

FIG. 4B is schematic view of the hydraulic pumping system of FIG. 4A. Here, the lift cylinder piston and operatively connected compressor cylinder piston are on their up strokes. Produced gas is being drawn into the compressor cylinder while oil is being brought to the surface.

FIG. 4C is an enlarged, cross-sectional view of the hydraulic cylinder, hydraulic cylinder rod, and lift piston as may be used in the hydraulic rod pumping system of FIG. 1, in one embodiment. Here, a position sensor is used along the rod.

FIGS. 5A and 5B together present a flow chart showing steps that may be performed for a method of compressing produced gas at an oil well site, in one embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Definitions

For purposes of the present application, it will be understood that the term “hydrocarbon” refers to an organic compound that includes primarily, if not exclusively, the elements hydrogen and carbon. Hydrocarbons may also include other elements, such as, but not limited to, halogens, metallic elements, nitrogen, oxygen, and/or sulfur.

As used herein, the term “hydrocarbon fluids” refers to a hydrocarbon or mixtures of hydrocarbons that are gases or liquids. For example, hydrocarbon fluids may include a hydrocarbon or mixtures of hydrocarbons that are gases or liquids at formation conditions, at processing conditions or at ambient conditions (15° C. to 20° C. and 1 atm pressure). Hydrocarbon fluids may include, for example, oil, natural gas, coalbed methane, shale oil, pyrolysis oil, pyrolysis gas, a pyrolysis product of coal, and other hydrocarbons that are in a gaseous or liquid state.

As used herein, the terms “produced fluids,” “reservoir fluids” and “production fluids” refer to liquids and/or gases removed from a subsurface formation, including, for example, an organic-rich rock formation. Produced fluids may include both hydrocarbon fluids and non-hydrocarbon fluids. Production fluids may include, but are not limited to, oil, natural gas, pyrolyzed shale oil, synthesis gas, a pyrolysis product of coal, carbon dioxide, hydrogen sulfide and water (including steam).

As used herein, the term “fluid” refers to gases, liquids, and combinations of gases and liquids, as well as to combinations of gases and solids, combinations of liquids and solids, and combinations of gases, liquids, and solids.

As used herein, the term “wellbore fluids” means water, mud, hydrocarbon fluids, formation fluids, or any other fluids that may be within a string of drill pipe during a drilling operation.

As used herein, the term “gas” refers to a fluid that is in its vapor phase at surface conditions.

As used herein, the term “subsurface” refers to geologic strata occurring below the earth's surface.

As used herein, the term “formation” refers to any definable subsurface region regardless of size. The formation may contain one or more hydrocarbon-containing layers, one or more non-hydrocarbon containing layers, an overburden, and/or an underburden of any geologic formation. A formation can refer to a single set of related geologic strata of a specific rock type, or to a set of geologic strata of different rock types that contribute to or are encountered in, for example, without limitation, (i) the creation, generation and/or entrapment of hydrocarbons or minerals, and (ii) the execution of processes used to extract hydrocarbons or minerals from the subsurface.

As used herein, the term “wellbore” refers to a hole in the subsurface made by drilling or insertion of a conduit into the subsurface. A wellbore may have a substantially circular cross section, or other cross-sectional shapes. The term “well,” when referring to an opening in the formation, may be used interchangeably with the term “wellbore.” The term “bore” refers to the diametric opening formed in the subsurface by the drilling process. (Note that this is in contrast to the term “cylinder bore” which may be used herein, and which refers to a hydraulic cylinder over a wellbore.)

DESCRIPTION OF SELECTED SPECIFIC EMBODIMENTS

FIG. 1 is a side view of a hydraulic oil well pumping system 100 of the present invention, in one embodiment. The hydraulic oil well pumping system 100 is used for producing hydrocarbon fluids from a subsurface formation 110 to the surface 101 at a well site. In addition, the hydraulic oil well pumping system 100 is used for compressing produced gas at the surface 101.

In FIG. 1, it is first seen that the system 100 includes an elongated lift cylinder 150. The lift cylinder 150 houses a lift cylinder rod 155. The lift cylinder rod 155 reciprocates up and down within the lift cylinder 150 in response to hydraulic pressure applied within the lift cylinder 150. Reciprocation creates an upstroke and a down stroke.

The lift cylinder rod 155 is mechanically connected to a harness system 140. The harness system 140 reciprocates with the lift cylinder rod 155. As will be discussed more fully below, reciprocation of the harness system 140 causes a polish rod 160 and connected rod string 130 to reciprocate within a wellbore 115. In addition, reciprocation of the harness system 140 causes a pair of compression cylinder rods to reciprocate at the surface 101.

At an upper end of the lift cylinder rod 155 is a piston 165. The piston 165 seals an annular area 167 formed between the lift cylinder rod 160 and the surrounding lift cylinder 150. The piston 165 prevents hydraulic oil from migrating into a chamber 169 above the piston 165. The annular area 167 is filled with a working fluid, which is preferably a clean hydraulic oil.

The piston 165 and connected polish rod 160 reciprocate within the lift cylinder 150 between two heads. A first or upper head 152 is placed at a distal end of the cylinder 150, while a second or lower head 154 is at a proximal end of the cylinder 150. The second head 154 has an internal bore that slidably receives the lift cylinder rod 155 during reciprocation.

The hydraulic oil well pumping system 100 also includes a pair of fluid lines 170, 175. A first fluid line 170 is an oil line. The oil line 170 is in fluid communication with the annular area 167 of the lift cylinder 150 just above the second (or lower) head 144. The oil line 170 injects and receives oil from the annular area 167 in order to move the piston 155 up and down within the lift cylinder 150. In this way, an up stroke and a downstroke are created for the piston 165 and mechanically connected rod string 130 and downhole pump.

In one aspect, the second fluid line 175 is essentially a vent line. The vent line 175 receives air and any leaked oil from the piston 165 during the upstroke. The vent line 175 is supported by one or more brackets 156 disposed along the outer wall of the lift cylinder 150. In another arrangement, the second fluid line 175 is a pressure line that allows oil to push the piston 165 down on the downstroke. Operation of a three-way proportional valve that directs the flow of oil through lines 170 and 175 in this embodiment is discussed further, below.

Related components of the hydraulic oil well pumping system 100 are shown schematically. These include a prime mover 182, a hydraulic pump 184, control valves 190, and a fluid reservoir 195. These components are optionally supported together on a movable skid 180.

The prime mover 182 provides power to the pump 184. The prime mover 182 may be a gasoline engine, a diesel engine, or other internal combustion engine. Alternatively, the prime mover 182 may be an electric motor. When the prime mover 182 is started, it activates the hydraulic pump 184. Beneficially, changing the operating speed of the prime mover 182 will vary the output of the pump 184. Further, control logic may be used in connection with a timer to cyclically turn the pump 184 on and off or to open and close control valves 190 as is known in the art. Thus, control valves 190 will include electrical circuitry.

The pump 184 serves to pump fluid into the oil line 170. The pump 184 is preferably a piston style pump. However, other types of pumps such as a vane-type pump may be employed. The pump 184 may be a fixed displacement pump or a variable displacement pump. A hydraulically driven air fan (not shown) may be used to force air across hydraulic and compressor coolers. This helps to keep components from overheating.

When the pump 184 is stopped, or when the valves 190 redirect flow away from the oil line 170, the valves 190 permit oil to return to the fluid reservoir chamber 195. This may be done, for example, through a restricted orifice. Oil returns to the fluid reservoir chamber 195 through the restricted orifice (or other valve) in response to gravitational forces applied to the piston 165 by means of the harness system 140 and connected rod string 130 and downhole pump.

The lift cylinder 150 and harness system 140 reside over a wellhead 105. The wellhead 105 serves to support a string of casing 108 that extends from the surface 101 and down into a wellbore 115. In addition, the wellhead 105 supports a string of production tubing 120 within the casing 108.

It is understood that FIG. 1 only shows the wellhead 105 and an upper portion of the wellbore 115, and that the wellbore 115 will actually extend many hundreds and, likely, many thousands of feet down into the earth surface 110. Further, it is understood that the wellbore 115 will employ not just one string of casing (such as casing string 108), but also several strings of casing (not shown) extending down to a producing formation having one or more zones of interest. Additionally, the production tubing 120 will extend down to at least a top zone of interest. Finally, it is understood that many wellheads reside over a so-called cellar (not shown) at the surface 101.

The wellhead 105 includes a set of control valves. One such valve is shown at 104, and may be referred to as a master valve. The valves are part of a “Christmas tree,” shown via bracket 102. The valves of the Christmas tree 102 direct the flow of production fluids and also permit an operator to inject treatment chemicals or to otherwise access the production tubing 120. The Christmas tree 102 controls formation pressure both within and on the back side of the production tubing 120. An annular area 125 is shown for the back side of the production tubing 120.

Residing below the Christmas tree 102 and within the wellbore 115 is a rod string 130. The rod string 130 is comprised of a plurality of long, slender joints of steel, known as sucker rods. Each sucker rod is typically 25 or 30 feet in length. The rod string 130 supports a pump (not shown) downhole. The pump, in turn, moves production fluids from the subsurface formation, up the production tubing 120, and to the wellhead 105 through positive displacement. The pump is generally positioned next to a perforated zone of the wellbore 115. The production fluids then flow from a valve in the Christmas tree 102, such as valve 104, where they may undergo some initial fluid separation and are then directed into a flow line or a gathering tank (not shown). (Note that a production line is not shown in FIG. 1, but those of ordinary skill in the art will well understand that reservoir fluid lines extend from a well site.

Each sucker rod includes a coupling. In FIG. 1, a coupling 134 is shown above the rod string 130. In this view, the coupling 134 connects the rod string 130 to a polish rod 160. The polish rod 160, in turn, extends up through the wellhead 105, and through the Christmas tree 102. Suitable packing 106 is provided to prevent production fluids from leaking out of the Christmas tree 102.

FIG. 2 is an enlarged side view of a portion of the hydraulic oil well pumping system 100 of FIG. 1. Here, the lift cylinder 150, the lift cylinder rod 155, the polish rod 160, the harness system 140 and the two compressor cylinders 145 are more clearly seen. In addition, a frame or a tripod is shown that is used to stabilize the lift cylinder 150 over the wellbore 115. This optional feature is most commonly used in windy locations. In the view of FIG. 2, the tripod includes an upper horizontal bar 141, a lower horizontal bar 147, and vertical bars 149. In the arrangement of FIG. 2, only two vertical bars 149 are shown. However, it is understood that a third vertical bar 149 is used, and resides behind the polish rod 160 and the lift cylinder rod 155.

The polish rod 160 defines an elongated cylindrical body. An upper portion of the polish rod 160 extends through a block 146 that is part of the harness system 140. A set of rod clamps 143 holds the polish rod 160 to the block 146. In this way, the polish rod 160 is mechanically connected to the harness system 140.

The harness system 140 includes a wheel, or pulley 148. A bridle cable 147 is wound around the pulley 148 and connects to the block 146. The pulley 148 and bridle cable 147, in turn, are connected to an upper support bar 144 of the harness system 140.

The upper support bar 144 includes several pins. First, pin 149′ pivotally connects the upper support bar 144 to the lift cylinder rod 155. Then, opposing pins 149″ pivotally connect the upper support bar 144 to the opposing compressor cylinder rods 142. In this way, as the upper support bar 144 reciprocates, the lift cylinder rod 155 and the compressor cylinder rods 142 also reciprocate.

FIG. 3 is a side cross-sectional view of a compressor system 300 of the present invention, in one embodiment. The system includes one of the compressor cylinders 145 of FIG. 1, in one embodiment, indicated at 345. The compressor cylinder 345 may be, for example, a six-inch i.d. barrel. The compressor cylinder 345 includes an upper end 312 and a lower end 314. The upper end 312 includes an outlet 316 that is in fluid communication with a fluid reservoir (shown schematically at 318), while the lower end 314 is closed.

A bore 305 is formed within the cylinder 345. The bore 305 houses a compressor cylinder rod 342. Compressor cylinder rod 342 corresponds to rods 142 of FIGS. 1 and 2. In the view of FIG. 3, the compressor cylinder rod 342 is in mid-stroke.

An annular area 315 is formed between the cylinder rod 342 and the surrounding cylinder 345. The annular area 315 is sealed at the bottom of the rod 342 using a suitable packer or seal. A piston 346 is seen sealing the annular area 315. The piston 346 is at least partially secured in place by a nut 361 that is threadedly connected to a threaded end 341 of the compressor cylinder rod 342. A spacer 363 is optionally placed between the piston 346 and the nut 361 to fill a void that may be left between the piston 346 and the nut 361.

Above the piston 346, the bore 305 is at least partially filled with oil. The oil is used for cooling and lubricating the cylinder 345. As the piston 346 moves on its upstroke, the lubricating oil moves through the outlet 316 and into the reservoir 318.

In one aspect, the fluid reservoir 318 is shared with the reservoir 195 for the hydraulic oil well pumping system 100. Check valves (not shown) are provided so that when the oil is pushed from the lift cylinder 155 (through oil line 170 during a down stroke), oil is drawn into the compressor cylinder 345 above the piston 346. During this movement, the oil is preferably passed through a suction filter (not shown). Then, when oil is pushed back into the lift cylinder (through oil line 170 during an upstroke), the oil is withdrawn from bore 305 above the compressor piston 346. However, it is preferred that reservoir 318 be separate from oil reservoir 195, and that different types of oils be used.

In one trip or the other, the working oil may be routed through an oil cooler. In this way the oil will not only keep the seals and pistons in the cylinders 150, 345 lubed, but will also take the heat from compressing the gas and dissipate it into the air through heat transfer provided by the cooler.

Below the piston 346, the bore 305 is in fluid communication with a pair of pipes 304, 330. Pipe 304 transmits non-condensable hydrocarbon fluids, or produced gas, from the wellbore (seen in FIG. 1 at 115) to the bore 305 below the piston 346. This takes place during an upstroke of the compressor cylinder rod 342 and piston 346. During this process, the produced gas (indicated at arrow “G”), is drawn through a one-way check valve 340i and into the bore 305 of the compressor cylinder 345. Then, on the down stroke, the produced gas is moved through one-way check valve 340o and into a dedicated gas line 330.

An upper end of the compressor cylinder rod 342 has a through-opening 349 The through-opening 349 is dimensioned to receive pin 149″. In this way, the rod 342 is pivotally connected to the upper support bar 144 of the harness system 140. This, in turn, allows compressor cylinder rod 342 to reciprocate with lift cylinder rod 155 and polish rod 160.

Preferably, pressure is monitored in the compressor cylinders 345 (or 145) above the compressor pistons 346 (or 146). Hoses (not shown) may be connected to top portions of the cylinders 345 to make sure that pressure is equal in the bores 305 of both cylinders 350. This keeps the upper support bar 144 from becoming unlevel. In addition, the bottom side of the respective pistons 346 is configured in such a way that when the compressor cylinder rods 342 are retracted, the bore 305 is evacuated in order to pull in as much gas as possible. This increases the efficiency of the gas compression. Preferably, the pistons 346 comprise durable elastomeric rings.

FIG. 4A is schematic view of a hydraulic pumping system 400 of the present invention, in one arrangement. The system 400 resides over wellbore 415, which corresponds to wellbore 115 of FIG. 1. Here, a lift cylinder piston 450 and an operatively connected compressor cylinder piston 442 are on their down strokes. Arrows “D” indicate the direction of the pistons 450, 442.

The hydraulic pumping system 400 includes a pump 184. The pump 184 is preferably a hydraulic pump, such as a fixed or variable displacement hydraulic pump. The hydraulic discharge of the pump 184 is controlled by a control valve. The control valve may be directed through a programmable logic controller. The control valve directs the movement of a lift piston 465 within the lift cylinder 450. Preferably, an approximately 87-inch stroke is provided.

The pump 184 is designed to pump a working fluid such as a clean or refined oil from the reservoir 195 through an oil line 170. This takes place during the upstroke, shown separately in FIG. 4B. En route to the lift cylinder 450, the oil may travel through a directional control valve (not shown). The control valve may be, for example, a proportional valve or it may be part of a variable speed prime mover. In any embodiment, the control valve allows hydraulic oil to be pumped from the pump 184 to an annular area (such as area 167 of FIG. 1) through oil line 170.

The hydraulic pumping system 400 also includes a return line 175 and a reservoir 195. A downstroke control valve (not shown) may be provided to permit oil to return to the fluid reservoir 195 via a restricted orifice. This takes place when the directional control valve is in its “neutral” position. Since pressure no longer forces the piston 465 upward, it begins to drop in response to gravitational forces applied to the piston 460 by means of the rod string 460 and connected downhole pump. This takes place during the downstroke presented in FIG. 4A.

In one aspect, the return line 175 serves as a pressure line. In this instance, line 175 is an upper oil line. Pressure may be provided to the upper oil line 175 during the downstroke as a means of controlling stroke length, cycle time, or both. Pressure may also be applied in line 175 at the end of the upstroke to prevent (or at least minimize) bumping or jarring of the piston 165 at the peak of the upstroke.

In one aspect, the main hydraulic directional control valve is a three-position proportional valve having load sense ports. The positions define an upstroke position, a downstroke position, and neutral. In the neutral position, ports placed in the lift cylinder 150 for the lower oil line 170 and the upper oil line 175 are blocked. The pump 184 will go into standby mode when it is not moving any oil. Both of the cylinder ports are blocked, holding the piston 165 in position.

The directional control valve will be part of the control valves shown at 190. The control valves 190 will operate with coils. As a first coil is energized, it sends a signal to open a port associated with oil line 170. This sends pressured oil to the bottom side of the lift piston 165, and simultaneously drains oil from the top side of the lift piston 165. Oil is sent to the reservoir 195, allowing the piston 165 to move in an upstroke. Then, the proportional control valve receives a new signal, such as a pulse-width modulation (“PWM” signal) from a processor (or programmable logic controller, or “PLC”) to discontinue the flow of oil into oil line 170. This preferably takes place in response to feedback from a position sensor strategically located along the lift cylinder 150 at the top of the piston stroke.

It is observed that the PWM signals may start out weak, and then increase to a desired level to provide smooth starts and stops. The signals control the maximum opening amount of valves and the open times. This cycling of signals also serves to control speed and stroke length. In this embodiment, separate upstroke and downstroke control valves are not required.

To begin the downstroke, a separate coil associated with the proportional control valve may be energized. This causes pressured oil to enter the lift cylinder 150 from the upper oil line 175 above the lift piston 165. At the same time, the port associated with the lower line receives a back flow of oil from below the piston 165. This process is again controlled by PWM signals from the PLC, with smooth starting and stopping. In one aspect, the PLC is a Maple Systems controller having a color touch screen.

It is noted here that many hydraulic drive/control units for hydraulic rod pumping systems are known. One such system is described in U.S. Patent Publ. No. 2009/0194291, filed by Petro Hydraulic Lift Systems, LLC of Jennings, La. (now part of Lufkin Industries, Inc. of Houston, Tex.) Aspects of such as system are suitable for use in the system 100 herein. The 2009/0194291 is incorporated herein in its entirety by reference.

In FIG. 4A, compressor cylinder piston 446 is moving down with the compressor cylinder rod 442. This simultaneously causes produced gas to move to a downstream facility 435 through line 430. The downstream facility 435 may be a gas separator or a treating unit (such as a cryogenic separator or an amine chemical separator). Alternatively, the downstream facility 435 may be a gathering facility for downstream transmission. Alternatively still, the downstream facility 435 may be a drill site where gas is gathered for use as a combustible fuel in driving engines on a drilling rig. Still further, where the gas is almost completely a clean burning fuel such as methane, the downstream facility 435 may simply be a tank used directly for fuel.

In one aspect, the wellbore 415 is about 6,500 feet in true-vertical depth. The weight of the rod string and connected downhole pump are about 9,000 pounds. In this instance, the force required to compress the gas in line 430 in both cylinders will be around 11,000 pounds at 225 psi line pressure. Therefore, the rod string 430 falling back down (as shown in FIG. 4A) will supply 9,000 pounds of force, while hydraulics will provide the additional 2,000 pounds as needed. If the well psi stays around 50 psi, then the compressor cylinders 445 will need to provide about 3,000 pounds of lift on the upstroke (as shown in FIG. 4B), reducing power requirements for the hydraulic system, thereby creating greater working efficiency.

It is noted that certain steps may be taken to increase efficiency of the hydraulic pumping system 400. These may include increasing the inner diameter of the compressor cylinders 445, thereby allowing more gas to flow into the line 430. These may also include turning the pump on and off as gas psi increases and decreases or as fluid volume increases or decreases from the wellbore 415.

FIG. 4B provides another schematic view of the hydraulic pumping system 400 of FIG. 4A. Here, the lift cylinder piston 465 and operatively connected compressor cylinder piston 442 are on their up strokes. In FIG. 4B, compressor cylinder piston 446 is moving up with the compressor cylinder rod 442. This causes produced gas from the wellbore 415 to be drawn into the compressor cylinder 445 below the piston 446. At the same time, oil is brought to the surface 401 and moved downstream through separate surface pipe 406.

It is noted that it is desirable for the operator to know where the piston 465 is within the cylinder 450 during any given part of the cycle. One reason is so that speed control may be applied to the pump 184. Specifically, the operator may wish to decrease the speed of the pump 184, and thus decelerate the piston 465 and rod string at the ends of the upstrokes and down strokes. This prevents bumping and jarring as discussed above.

Hydraulically actuated reciprocating sucker rod pump systems have historically employed sensors along or above the wellhead. The sensors may be mechanical, hydro-mechanical, pneumatic, pneumatic-mechanical, acoustic, electronic or electro-mechanical position indicating devices used to detect the position of a piston. For example, U.S. Pat. No. 7,762,321 teaches the use of a plurality of “proximity switches” along the actuation cylinder to detect the location of an object along the piston. When a proximity switch detects the object, a limit switch is activated that de-energizes a valve. Sensors have also been used to detect travel speed or direction and are used to send signals to a process that may control piston position, speed or direction. The system 400 is compatible with the use of such sensors and control systems.

FIG. 4C demonstrates one possible use of a sensor for the hydraulic rod pumping system 100. A sensor 455 is shown proximate an upper end of the hydraulic cylinder rod 155. The sensor 455 interacts with a magnet 450 to provide location, or position, of the piston 165.

In the view of FIG. 4C, the hydraulic cylinder 150 is seen in an enlarged view. The hydraulic cylinder 150 defines a tubular wall 413 that houses the elongated lift cylinder rod 155. The lift cylinder rod 155 moves between upper and lower rod positions in response to hydraulic pressure applied to the piston 165. The lift cylinder rod 155 is affixed to the lift piston 165, and travels with it. In the arrangement of FIG. 4C, the lift cylinder rod 155 actually extends through a cap 436 and above the hydraulic cylinder 150.

Also visible in FIG. 4C is an enlarged upper portion of the frame that is used to stabilize the lift cylinder 150 over the wellbore. The frame again includes an upper horizontal bar 141, a lower horizontal bar (not shown in FIG. 4C), and three (or more) vertical bars 149. The frame 149 forms an interface between the cylinder wall 413 and the wellhead (seen at 105 in FIG. 1).

At the lower end portion of the lift cylinder rod 155 is provided the harness 140. Only an upper portion of the harness 140 is shown in FIG. 4C. It is understood that the harness supports the polish rod, shown at 160 in FIG. 1, and seen partially at the bottom of FIG. 4C.

The hydraulic cylinder 150 includes an upper port 475 and a lower port 470. The upper port 435 can be a part of cap 436 which is fastened to an upper end portion of the cylinder body 213. FIG. 4C illustrates a condition wherein the piston 165 is at the peak of its upstroke, as indicated by arrows 441. Lower port 470 is receiving inflow of hydraulic fluid as indicated by the arrows 440. Fluid above piston 165 is evacuated via upper port 475. Arrows 442 indicate schematically the flow direction of oil as the piston 165, lift cylinder rod 155, and polish rod 160 are elevated. The harness system 140 (shown in FIG. 1) will also be elevated.

The magnet 450 is mounted on top of a cap 436. Upper port 475 extends into the cap 436. The magnet 450 communicates with the position sensor 455. The position sensor 455 is illustratively used in lieu of proximity sensors or switches. Preferably, the sensor 455 actually resides within a hollow lift cylinder rod 155. The sensor's proximity to the magnet 450 determines the location of the piston 165 at all times.

Using the hydraulic rod pumping system 100 described above, a method for compressing produced gas at a well site is also provided herein. FIGS. 5A-5B provide a flow chart showing steps that may be performed for such a method 500, in one embodiment. In the method, the well site has a wellbore that extends into an earth surface. The method 500 employs a pumping system as described above, including a pump with an oil line that cyclically directs hydraulic fluid into a lift cylinder over a wellhead. The pressure created by the hydraulic fluid causes a piston and operatively connected rod string and downhole pump to reciprocate. This, in turn, causes reservoir fluids to be produced from the wellbore to the surface through positive displacement.

Referring now to FIG. 5A, the method 500 first comprises providing an elongated hydraulic lift cylinder. This is shown at Box 510. The lift cylinder is positioned over the wellbore such as in the arrangement shown in FIGS. 1 and 4A.

The method 500 also includes providing a lift piston. This step is provided at Box 515. The lift piston may be in accordance with the piston 165 of FIG. 1. The lift piston is movable between upper and lower rod positions within the lift cylinder. The lift piston creates an annular seal below the piston between a connected lift cylinder rod and the surrounding lift cylinder. Hydraulic pressure acts against the lift piston to cause the lift piston to move.

The method 500 further includes operatively connecting the lift piston to a rod string. This is done through a harness system (such as system 140 of FIG. 1) that mechanically connects the lift cylinder rod with a polish rod and connected rod string. This is shown at Box 520. When the lift piston reciprocates, the polish rod and connected rod string reciprocate with it. Preferably, the rod string moves within a string of production tubing that extends down to the depth of a subsurface reservoir.

The rod string extends downwardly from the polish rod and into the wellbore. The rod string has a downhole pump connected to it for lifting fluids to the surface in response to reciprocation of the rod string.

The method 500 also includes providing a hydraulic pump. This is seen at Box 525. Preferably, the pump is a variable displacement pump. The pump is powered by a prime mover. The prime mover may be an electric motor, an internal combustion engine, or other driver.

The method 500 also has the step of connecting the pump and the hydraulic cylinder with an oil line. This is indicated at Box 530. The oil line transmits hydraulic fluid from the pump to the lift cylinder.

Optionally, the method 500 includes providing a directional control valve. This is given at Box 535. The directional control valve moves between upstroke and downstroke flow positions in response to signals from an electrical control system. When the valve is in its open position, it directs hydraulic fluid such as oil from the pump, through the oil line and into an annular area formed between the piston and the surrounding lift cylinder. In the neutral position, the control valve allows oil to flow back from the lift cylinder to the reservoir through a downstroke control valve.

The method 500 also has the step of providing a fluid reservoir. This is shown at Box 540. The reservoir contains hydraulic fluid to be supplied to the pump. During operation, the hydraulic fluid level will rise and fall in the reservoir chamber on each stroke of the lift piston.

The method 500 next includes providing a reservoir line. This is seen at Box 545. The reservoir line transmits hydraulic fluid from the lift cylinder back to the reservoir. Optionally, a filter is provided along the reservoir line.

The method 500 optionally also has the step of providing a down stroke control valve (not shown). The downstroke control valve may have various passages allowing unrestricted flow in one direction (the upstroke direction), and restricted flow in the other direction (the downstroke direction). The down stroke control valve chokes the flow of fluid from the cylinder back to the reservoir. This, in turn, limits the rate of flow of hydraulic fluid. The downstroke control valve may be a discrete valve. Alternatively, he downstroke control valve may be a nitrogen accumulator or any other device that captures the energy from the gravitational fall of the piston and connected polish rod, rod string and downhole pump.

Also, the method 500 includes providing at least one compressor cylinder. This is indicated at Box 550. Each compressor cylinder has a compressor piston that is movable between upper and lower rod pistons in response to movement of the lift piston. Thus, the compressor pistons are operatively connected to the lift pistons so that when hydraulic pressure reciprocates the lift piston and operatively connected rod string, the at least one compressor cylinder is also reciprocated.

In addition, the method 500 includes placing the at least one compressor cylinder in fluid communication with a gas line. This is provided at Box 555. The line resides at the surface and is used to transport non-condensable hydrocarbon fluids such as methane and ethane. Additional components of the non-condensable hydrocarbon fluids may include hydrogen sulfide, carbon dioxide, propane, and argon. The non-condensable hydrocarbon fluids are permitted to invade the compressor cylinders below the respective compressor pistons during upstrokes of the compressor cylinder rods.

Further, the method 500 has the step of producing non-condensable hydrocarbon fluids from the wellbore and into the gas line. This is shown at Box 560. Production is preferably done by allowing gases to migrate from a subsurface reservoir and up the wellbore behind the string of production tubing. The gases are directed into the gas line by the wellhead.

The method 500 additionally provides for reciprocating the at least one compressor piston in order to increase pressure in the gas line. This is seen at Box 565. When the compressor piston moves on its upstroke, it draws gas in from the wellbore and into the bore of the compressor cylinder. Then, when the compressor piston moves down on its downstroke, it compresses the gas and moves the gas along the gas line downstream.

Also, the method 500 includes reciprocating the lift piston and mechanically connected rod string within the wellbore. This is indicated at Box 570. The step of Box 570 is the natural result of operation of the hydraulic pumping system in order to pump oil from the wellbore.

It is observed that during the design of the hydraulic oil well pumping system 100, a stroke length must be determined for the lift piston and connected lift cylinder rod. The stroke length will impact the designed length for the lift cylinder. Of course, the stroke length will also affect the rate in which fluids are produced to the surface by the connected submersible pump.

In addition, the stroke length of the lift piston will impact the designed length for the compressor cylinders and the housed compressor cylinder rods. Those of ordinary skill in the art will, based on this disclosure, understand that the dimensions of the lift cylinder rod and the compressor cylinder rod need not be identical; however, the lift cylinder (150 in FIG. 1) and the compressor cylinder (145) preferably need to be able to accommodate the same stroke length for the lift piston (165) and the compressor pistons (146).

Additionally still, ring the design of the hydraulic oil well pumping system 100, a determination may be made concerning volume of the compressor cylinder below the compressor piston. A larger bore volume permits a greater volume of gases to be received and handled at the surface. It will be understood though that a greater volume of gases may require greater horsepower, or force, from the lift piston during the downstroke. Hence, the proportional valve embodiment described above may be of benefit in helping the rod string “push” the compressor piston down against the non-condensable fluids and through the gas line.

As can be seen, a method for compressing gas while pumping oil, used specifically for actuating a sucker rod string and bottom hole plunger pump in oil or gas wells, is offered herein. It is understood that the hydraulic oil well pumping system 100 of FIG. 1 and the method 500 for compressing gas of FIG. 5 are merely illustrative. Other arrangements may be employed in accordance with the claims set forth below. Further, variations of the method for determining position of the piston may fall within the spirit of the claims, below.

For example, while embodiments described herein have provided for the oil line 175 actuating the lift piston 165 and mechanically connected polish rod 160 and rod string 130, and the harness system 140 thereby moving the compressor cylinder rods 142 in response, that the inverse could also be applied. In this respect, the oil line 175 may act against respective lift pistons (not shown) in upper ends of the compressor cylinders 145, causing direct reciprocation of the compressor cylinder rods 142 and, thereby, consequential reciprocation of the list piston 165 through the harness system 140. It will be appreciated that the inventions are susceptible to other such modifications, variations and changes without departing from the spirit thereof.

Claims

1. A hydraulic oil well pumping system, comprising:

an elongated hydraulic lift cylinder;

a lift piston that is movable between upper and lower rod positions within the lift cylinder;

a rod string that is operatively connected to the lift piston, the rod string being configured to extend into a wellbore;

a downhole pump positioned in the wellbore proximate a lower end of the rod string for pumping reservoir fluids up the wellbore;

at least one compressor cylinder; and

a compressor piston residing within each of the at least one compressor cylinder, the compressor piston being configured to reciprocate within the compressor cylinder in response to movement of the lift piston and the operatively connected rod string;

wherein the at least one compressor cylinder is in fluid communication with a gas line that receives non-condensable fluids produced from a wellbore below the compressor piston such that pressure is added to the gas line when the compressor piston moves on a down stroke.

2. The hydraulic oil well pumping system of claim 1, further comprising:

a hydraulic pump configured to cyclically pump a work fluid into a bore of the lift cylinder to act on the lift piston.

3. The hydraulic oil well pumping system of claim 1, further comprising:

a prime mover;

a hydraulic pump that is powered by the prime mover;

a control valve that moves between upstroke and down stroke flow positions;

an oil line connecting the pump and the hydraulic cylinder, the control valve being positioned in the oil line so that it can direct flow between the hydraulic pump and the lift cylinder;

a fluid reservoir for containing hydraulic fluid to be supplied to the pump.

4. The hydraulic oil well pumping system of claim 3, further comprising:

a reservoir line that transmits hydraulic fluid from the cylinder to the reservoir; and

wherein the hydraulic fluid is a refined oil.

5. The hydraulic oil well pumping system of claim 3, wherein:

the prime mover is an electric motor or an internal combustion engine; and

the rod string is mechanically connected to the piston through a polish rod.

6. The hydraulic oil well pumping system of claim 1, wherein the non-condensable fluids comprise methane, ethane, or combinations thereof.

7. The hydraulic oil well pumping system of claim 1, wherein the gas line is in fluid communication with (i) a gas treating unit in an oil field, (ii) a gas gathering facility, or (iii) a storage tank in an oil field.

8. The hydraulic oil well pumping system of claim 1, wherein:

the non-condensable fluids comprise primarily methane, ethane, or combinations thereof; and

the gas line is in fluid communication with a storage tank at a drill site.

9. The hydraulic oil well pumping system of claim 1, wherein the lift piston is operatively connected to the rod string by means of:

a lift cylinder rod connected to the lift piston and that extends below the lift cylinder;

a polish rod that extends through a well head and into the wellbore, and is coupled to the rod string; and

a harness system connected to a lower end of the lift cylinder rod, and also connected to an upper end of the polish rod, the harness system having a block for receiving an upper end of the polish rod and a clamp for securing the polish rod over the block.

10. The hydraulic oil well pumping system of claim 8, further comprising:

a compressor cylinder rod residing with each of the at least one compressor cylinder, with each of the compressor cylinder rods being operatively connected to a respective compressor cylinder piston proximate a lower end, and to the harness system at an opposing upper end such that the compressor cylinder piston and connected compressor cylinder rods reciprocate with the lift piston and connected lift cylinder rod.

11. A method of compressing produced gas at a well site, the well site having a wellbore that extends into an earth surface, and the method comprising:

providing an elongated hydraulic lift cylinder, the lift cylinder having a lift piston that is movable between upper and lower rod positions within the lift cylinder;

operatively connecting the lift piston to a rod string, wherein the rod string extends downwardly from the lift piston and into the wellbore;

providing a downhole pump in the oil well proximate a lower end of the rod string;

providing a hydraulic pump that is powered by a prime mover;

fluidically connecting the hydraulic pump and the hydraulic cylinder with an oil line that cyclically transmits hydraulic fluid from the pump into the lift cylinder to act against the lift piston;

providing at least one compressor cylinder, each of the at least one compressor cylinder having a compressor piston that is movable between upper and lower rod positions with reciprocating movement of the lift piston;

placing the at least one compressor cylinder in fluid communication with a gas line;

producing non-condensable hydrocarbon fluids from the wellbore and into the gas line;

reciprocating the lift piston and operatively connected rod string and downhole pump in order to pump condensable hydrocarbon fluids from the wellbore to a surface; and

reciprocating the compressor piston with the lift piston in order to increase pressure in the gas line and move the non-condensable hydrocarbon fluids through the gas line.

12. The method of claim 11, further comprising:

providing a directional control valve that moves between upstroke and downstroke flow positions such that when the valve is in its upstroke position, it directs the hydraulic fluid from the pump and into an annular area formed below the lift piston between a lift cylinder rod and the surrounding lift cylinder, and when the directional control valve is in its downstroke position, it receives reverse flow from the lift cylinder; and

providing a fluid reservoir for containing hydraulic fluid to be supplied to the pump.

13. The method of claim 12, wherein:

the method further comprises providing a reservoir line that transmits hydraulic fluid from the cylinder to the reservoir; and

the hydraulic fluid is a refined oil or an aqueous fluid.

14. The method of claim 13, wherein:

the prime mover is an electric motor or an internal combustion engine; and

the rod string is mechanically connected to the piston through a polish rod.

15. The method of claim 11, wherein the non-condensable hydrocarbon fluids comprise methane, ethane, or combinations thereof.

16. The method of claim 15, further comprising:

transporting the non-condensable hydrocarbon fluids through the gas line to (i) a gas treating unit in an oil field, (ii) a gas transmission line, (iii) a storage tank in an oil field, or (iv) a storage tank at a drill site.

17. The method of claim 11, wherein:

the lift piston is connected to a lift cylinder rod within the lift cylinder, the lift cylinder rod extending below the lift cylinder; and

a polish rod extends through a well head and into the wellbore, and is coupled to the rod string.

18. The method of claim 17, wherein operatively connecting the lift piston to the rod string comprises connecting a lower end of the lift cylinder rod to a harness system, and connecting an upper end of the polish rod to the harness system, the harness system having a block for receiving an upper end of the polish rod and a clamp for securing the polish rod over the block.

19. The method of claim 18, wherein the lift cylinder rod and the polish rod are the same rod.

20. The method of claim 18, wherein:

each of the compressor cylinders comprises a compressor cylinder rod; and

each of the compressor cylinder rods is operatively connected to a respective compressor cylinder piston proximate a lower end, and to the harness system at an opposing upper end such that the compressor cylinder piston and connected compressor cylinder rods reciprocate with the lift piston and connected lift cylinder rod.